Modern mobile devices, such as tablet computers and mobile phone such as smartphones, often have both wireless networking (such as Wifi also referred to as 802.11x) connectivity and radio access network (such as EVDO, UMTS, HSPA, and LTE) connectivity. Such devices are typically associated with a mobile network carrier that has a geographically confined radio access network, but the carrier also often has roaming agreements with other carriers so that when a customer of a particular carrier visits a country served by a second carrier, the customer will be preferentially directed to use the services of the second carrier.
The roaming of a mobile device between networks is a well known technology, and the Radio Access Network part of the roaming is well known and documented. However, the manner in which a device roams when both radio access networks (such as those compliant with the 3rd generation partnership project (3GPP) standards) and wireless networking access methods (such as those compliant with IEEE 802.11x standards) can be used is less clear.
As specified in 3GPP TS 23.402, when away from its home network a mobile device or other such user equipment (UE) selects an evolved packet data gateway (ePDG) based the Public Land Mobility Network (PLMN) ID. In a conventional roaming scenario, a UE receives a list of roaming networks that are available, and one of the networks can be selected, either in an automated fashion or through manual user selection. Based on the received visiting PLMN (vPLMN) ID, a UE can create a fully qualified domain name (FQDN), and based on the response from a domain name system (DNS) query on the created FQDN, an ePDG ID is selected, and an IPSec tunnel is establish. Typically, the creation of the FQDN is governed by rules set out in 3GPP TS 23.003 and the FQDN takes the form of “epdg.epc.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org”, where the PLMN ID provide a mobile country code (MCC) and a mobile network code (MNC). If the vPLMN ID is unknown, the UE can construct a FQDN using its home PLMN ID.
A problem has arisen, that for a number of different reasons, some types of user equipment do not receive a roaming network list (e.g. when roaming to a region that does not support the RAN access type of the device) and when roaming is done over a non-3GPP access technology (such as WiFi). In such cases, there is no standardized solution for the UE to obtain the vPLMN ID. At present, this situation is addressed by the UE using the hPLMN ID.
As the reference architectures for Fixed Mobile Convergence (FMC) scenarios listed in TR 23.839, a hPLMN might have roaming agreements with several vPLMNs. A vPLMN can have business agreements with several Broadband Forum (BBF) domains, and vice versa as shown in FIG. 1. As shown in FIG. 1, a UE 50 is associated with a home PLMN 52. The UE is roaming and is connected to VPLMN #2 54 which has provided access to BBF #1 54. Thus, UE 50 is connected to HPLMN 52 though a combination of BBF #1 wifi network 54 and VPLMN #2 56. BBF#1 54 has a wifi network and has business relationships with VLPMN #3 58 which also has a roaming agreement with HPLMN 52. From this, one can see that the use of a BBF compliant Wifi network does not provide sufficient information about the roaming activities of the UE. VPLMN #1 60 also has a business relationship with BBF #1 54, but has no roaming agreement with HPLMN 52. A second wifi access provider BBF #2 also has business relationships with each of the VPLMNs.
As specified in 3GPP TS 24.302: the trust relationship of a non-3GPP IP access network is determined by the home PLMN operator. That trust relationship is indicated to the UE via the following methods:
Pre-configured policies in the UE by the home PLMN operator.
Dynamic indication during 3GPP-based access authentication.
When the access network is detected as an un-trusted access, the UE typically selects an ePDG using the hPLMN ID or vPLMN (at roaming case).
In these roaming scenarios, if the UE selects the ePDG that belongs to hPLMN, the UE traffic is routed to the hPLMN via the SWu/SWn interface. According to the IP routing implemented the SWu/SWn may not traverse the vPLMN. The S9* session may be established via V-PCRF or directly between the hPCRF and the BPCF, if allowed by agreement between the parties and the network configuration.
With implementation of the above, the UE traffic will bypass the VPLMN completely—the Internet becomes the transport network between the BBF domain and the hPLMN. The roaming scenario basically becomes a non-roaming scenario. In some cases, this might be a problem for the roaming agreement between partners. In other cases, some network initiated push service, e.g. policy control traffic, may not work without a roaming partner. Accordingly, a non-3GPP roaming mechanism that allows a roaming UE to find the correct v-EPDG, whether it can find the vPLMN ID or not is desirable.
One proposed solution is that when a device connects to a non-3GPP network, it will default to use the ePDG of the home network. The UE can connect to the ePDG through the Internet, and thus be governed by the policies of the PGW and the ePDG in home network. Although this provides a degree of management, it bypasses the closer v-eEPDGs, making the method less efficient, and could result in actions that violate currently agreed-upon roaming agreements.
Therefore, it would be desirable to provide a system and method that obviate or mitigate the above described problems